Ferrous alloy and abrasive resistant articles made therefrom

ABSTRACT

A very high carbon, high vanadium alloy steel is prepared in which there is a specific relationship between carbon and vanadium, said steel containing chromium and molybdenum levels, together with balanced carbon and vanadium contents, so as to render said steel forgeable. Forged articles made from said steel after heat treatment to a hardness of 59 to 67 Rockwell C are highly resistant to abrasion and are suitable for a wide variety of uses where a wear resistant steel is required and conventional manufacturing techniques are employed.

[ FERROUS ALLOY AND ABRASIVE RESISTANT ARTICLES MADE THEREFROM [75]Inventors: Richard J. Henry, Latrobe; Robert A. Cary, Greensburg, bothof Pa.

[73} Assignee: Teledyne Mid-America Corporation, Los Angeles, Calif.

[22] Filed: Mar. 12, 1973 [21] App]. No.: 339,656

[52] [1.8. Cl 198/37, 75/126 A, 75/126 C, 75/126 E, 75/126 H, 75/128 B,75/128 D,

[51] Int. Cl... C22c 39/14, C22c 39/26, C22c 39/54 [58] Field of Search75/126 E, 128 V, 126 A, 75/126 C, 126 H, 128 D, 128 B, 128 W; 148/38, 37

[56] References Cited UNITED STATES PATENTS 1,982,421 1 H1934 Emmons148/3 1 2,575,219 1 H1951 Giles 75/126 E 1 Mar. 4, 1975 2,644,747 7/1953Eder 75/128 v 2,662,010 12/1953 Ahles 75/126 E 2,949,356 8/1960 Hughes75/128 v 3,692,515 Fletcher 75/126 E Primary E.\'aminerC. LovellAssistant E.\'aminerArthur J. Steiner Attorney, Agent, 0r,FirnzJohnston,Keil, Thompson & Shurtleff [57] ABSTRACT A very high carbon, highvanadium alloy steel is prepared in which there is a specificrelationship between carbon and vanadium, said steel containing chromiumand molybdenum levels, together with balanced carbon and vanadiumcontents, so as to render said steel forgeable. Forged articles madefrom said steel after heat treatment to a hardness of 59 to 67 RockwellC are highly resistant to abrasion and are suitable for a wide varietyof uses where a wear resistant steel is required and conventionalmanufacturing techniques are employed. 4

12 Claims, 3 Drawing Figures FERROUS ALLOY AND ABRASIVE RESISTANTARTICLES MADE THEREFROM BACKGROUND bon and 12% vanadium but an airhardening steel of this analysis is extremely difficult to forge and tocut in the annealed condition. Similarly, forgeable steels can be madewith 9% vanadium and 3% carbon but forgeable analyses do not harden allthe way through. Steels of this general type are disclosed in U.S. Pat.Nos. 2,174,281 to 2,174,286.

Typical wear resistant alloys which are commercially available are AISIA-7 which has a nominal weight percent analysis of 2.30% carbon, 0.40%silicon, 0.70% manganese, 1.10% tungsten, 1.10% molybdenum, 5.25%chromium and 4.75% vanadium, and AISI D-7 having the same analysisexcept that the weight percent of manganese content is 0.40, the weightpercent of chromium is 12.50, the weight percent of vanadium is 4.00 andthe alloy contains no tungsten. Alloys of these general types aredescribed in U.S. Pat. Nos. 2,575,219 and 2,575,218, respectively.Higher carbon-vanadium alloys are not commercially produced because ofmanufacturing problems.

OBJECTS One of the objects of this invention is to provide new andimproved ferrous alloy steels.

A further object is to provide new and improved ferrous alloy steelswhich are forgeable.

Another object of the invention is to provide abrasive resistantarticles made by forging the aforesaid new and improved ferrous alloysteels.

A further object of the invention is to provide a new and useful ferrousalloy steel which can be forged. into various types of articles usingstandard manufacturing techniques which articles can be heat treated bystandard methods and can be hardened all the way through.

Other objects and advantages of the invention will appear from thefollowing description in conjunction with the accompanying drawings.

THE DRAWINGS In the drawings: FIG. 1 illustrates graphically the heattreating data for a composition of the invention showing the asquenchedhardness as a function of austenitizing tem- BRIEF SUMMARY OF THEINVENTION In accordance with the invention a ferrous alloy steel isprovided having the following chemical analysis:

Ingredients Percent by Weight Carbon 2.2-3 .5 Chromium 2.5-5 .0 Vanadium6.0- l 0.0 Molybdenum 1.5-3 .0 Silicon 0 -1 .0 Sulfur 0 -0.03 Tungsten 0l .0 Nickel 0 -3 .0 Phosphorus 0 41.03 Manganese 0 -1 .0 Cobalt 0 5 .0

the remainder consisting essentially of iron, the relationship betweencarbon and vanadium being determined by the equation:

C= 1.25 0.236[V [0.7 0.18(V 0.7)]]

where C is carbon, V is the level of vanadium within the range of 6.0 to10.0% and [0.7 0.18(V 0.7)] is the amount of vanadium dissolved in thesteel matrix.

Despite the high carbon and high vanadium contents, a ste l 2f the.fstes9 nasqmnsrs al a a ysis. is forgeable provided suitable chromiumand molybdenum levels are used. The weight ratio of chromium tomolybdenum is preferably within the range of 1.35:1 to 1.85:1,preferably 1.35:1 to 1.45:1. These steels are forgeable at temperatureswithin the range of 2,050F. to 2,200F. Forged articles produced fromthese steels can be heat treated to a Rockwell C hardness within therange of 59 to 63 by conventional methods and within a range of 65 to 67by deep freezing at F. for 1 hour. Their wear resistance as shown by astandard grindability test is approximately three. times greater than acommercial wear resistant steel AISI A-7.

DETAILED DESCRIPTION OF THE INVENTION Within the range of chemicalcomposition previously given, especially good results are obtained bypreparing ferrous alloy steelscontaining 2.9% to 3.1% by weight carbon,2.5% to 3.0% by weight chromium, 8.75% to 9.25% by weight vanadium, 1.8%to 2.2% by weight molybdenum, 0.75% to 1.0% by weight silicon, a maximumof 1.0% by weight tungsten, a maximum of 1.0% by weight nickel, 0.4 to0.6% by weight'manganese, a maximum of 1.0% by weight cobalt, a maximumof 0.03% sulfur and a maximum of 0.03% phosphorus.

In evaluating the compositions of the invention different alloys havingchemical analyses within the aforementioned limits were prepared andpieces 21 inches long and 7 inches in square cross section were forgedon a 1,000 ton press at a temperature within the range of 2,050 to2,150F. These pieces were then subjected to heat treatment in order toproduce a Rockwell C hardness within the range of 59 to 63. They werealso subjected to a deep freeze treatment at 100F. for 1 hour to raisethe Rockwell C hardness to within the range of 65 to 67.

In a typical heat treatment, the ferrous alloy article is austenitizedfor 30 minutes at 1,.750F., quenched in air or in a straightening press,tempered for 2 hours at 350F. with air cooling and tempered for 2 hoursat 300F. with air cooling. This will usually produce a hardness of 61/62Rockwell C.

Additions of silicon, manganese and tungsten may be made to the ferrousalloy composition in amounts up to dard grindability test in whichgrindability is determined as a ratio of volume of metal removed fromthe specimen to volume removed from the grinding wheel. Comparisons werealso made with other wear resistant 1% to suit accepted meltingpractices without detri- 5 steels and the results are shown in thefollowing table mental effect. (Table I):

TABLE 1 Austeni- Tempering Grindability tizing Temp- TemperadicesHardness perature ture Rockwell C" Grade F. F. 1 2 Avg.

B-292l 1500 400 .28 .24 .26 60.8 1750 400 .28 .30 .29 61.1 1750 600 .30.30 .30 60.1 AlSl A-7 1775 275 .91 .85 .88 65.2 AlSl T-l5 2250 1000 .52.49 .51 67.3 AlSl M-4 2225 1000 .56 .55 .56 65.5

Additions of cobalt up to 5% and nickel up to 3% In the foregoing tableB-2921 represents a composimay be made without detriment to performancebut are not recommended since these elements raise cost withoutsubstantially improving performance.

While the actual equation showing the relationship between carbon andvanadium is the one previously stated, a simplified equation to obtainthe best combination of wear resistance and forgeability is: C isapproximately l.l 0.2% V where C is carbon and V is vanadium. Materiallyhigher carbon contents reduce forgeability and response to heattreatment. Materially lower carbon contents reduce forgeability and wearresistance.

The invention will be further illustrated but is not limited by thefollowing examples in which the quantities are by weight unlessotherwise stated.

EXAMPLE I Two short 7 inch ingots (300 pounds) were cast from airinduction furnaces. The chemical compositions were as follows:

An attempt was made to forge the ingots on a 1,000 ton press attemperatures within the range of 2,050F. to 2,150F. Heat B2920 did notforge. Heat B2921 forged surprisingly well.

Forged specimens from heat B2921 were then heat treated as shown inFIGS. 1 to 3. FIG. 1 represents the as quenched hardness as a functionof austenitizing temperature for three quenching media. The specimenswere hardened to a minimum hardness of 65 Rockwell C in oil, salt andair by quenching from 1,500F., 1,625F. and 1,675F., respectively.Tempering data as presented in FIGS. 2 and 3 show the tempered hardnessas a function of austenitizing temperature. The general curve shape isthe same for tempered and as quenched data? Maximum hardness is about 65Rockwell C for a 400F. temper, 63 Rockwell C for a 600F. temper, afteraustenitizing at 1,750F.

The various specimens were then subjected to a stantion of the inventionand the last three compositions are commercially available steels. Thechemical composition of AISl A-7 has previously been given herein. AISIT-15 is a high speed tungsten-cobalt type steel containingthe followingweight percentages of chemical elements:

carbon 0.30% manganese 0.30% silicon 4.50% chromium 5.00% vanadium13.00% tungsten 0.50% molybdenum 5 .00% cobalt AlSl M-4 is atungsten-molybdenum type high speed steel containing the followingweight percentages of chemical elements:

1 .30% carbon 0.30% manganese 0.30% silicon 4.50% chromium 4.00%vanadium 6.00% tungsten 4.50 molybdenum EXAMPLE II Heat A-964l wasprepared with the following chemical analysis in weight percentages:

2.90% carbon 0.97% silicon 0.37% manganese 0.03% sulfur 0.007%phosphorus 2.96% chromium 2.03% molybdenum 8.60% vanadium Thiscomposition forged well and the laboratory test for wear resistanceshowed a grindability index of 0.29. A brick mold liner prepared fromthis composition was used effectively in the manufacture of 7,100 brickswhereas a similar mold liner made from AlSl A-7 was effective for themanufacture of only 3,000 bricks. In additional tests the ferrous alloyfrom heat A-9641 has out-performed AlSl A-7 by a margin of 3:1.

The invention makes it possible to prepare high carbon, high vanadiumferrous alloys which are forgeable. Articles made from these alloys havea wear resistance approximately three times as great as commerciallyacceptable materials such as AlSl A-7. Generally accepted heat treatmentmethods can be used to obtain desired properties and generally acceptedmanufacturing techniques can be employed to make various types ofarticles.

The ferrous alloys of the invention are especially useful for themanufacture of liners for brick molds, liners for shot blastingequipment, liners for sand slingers, extrusion dies for ceramics,blanking rings and punches for saws, deep drawing dies, drawing dies forwire and special shapes, crane roller bushings, meat slicer blades, wearplates, rolls, forming dies, gauges, slitters and cutters, and wearedges.

Inasmuch as the grindability index of articles made from ferrous alloysteels in the manner previously described usually does not exceed threetenths, it will be recognized that the invention is applicable to manyhigh wear applications in the refractories industry and in otherindustries.

The invention is hereby claimed as follows:

1. A ferrous alloy steel having the following chemical analysis:

the remainder consisting essentially of iron, the relationship betweencarbon and vanadium being determined by the equation:

C 1.25 -l- 0.236 [V,, [0.7 +0.l8(V 0.7)]] where C is carbon, V is thelevel of vanadium within the range of 6.0 to 10.0% and [0.7 0. 18(V0.7)] is the amount of vanadium dissolved in the steel matrix, saidcomposition capable of being forged, austenitized, quenched and temperedto produce a substantially tempered martensitic structure which shows ahardness of about 59-67 Rockwell C and a grindability index notexceeding approximately 0.3.

2. A ferrous alloy steel as claimed in claim l in which the ratio ofchromium to molybdenum is within the range of 1.35 to 1.85.

3. A ferrous alloy steel as claimed in claim 1 having the followingchemical analysis:

Ingredients Percent by Weight Carbon 2.9-3. 1 Chromium 2.5-3.0 Vanadium8.75-9.25 Molybdenum 1.8-2.2 Silicon 0.75-l.0 Sulfur 0-0.03 Tungsten 0-l.0 Nickel O-l .0 Phosphorus 0-0.03 Manganese 0.4-0.6 Cobalt O-l .0.

4. A ferrous alloy steel as claimed in claim 3 in which the ratio ofchromium to molybdenum is within the range of 1.35 to 1.45.

. 5. A ferrous alloy steel as claimed in claim 1 having the followingapproximate chemical analysis in weight percentage:

carbon 2.93% silicon 0.76% manganese 0.23% sulfur 0.01 8% phosphorus0.0l 1% chromium 2.74% vanadium 8.76% molybdenum 1.96%.

6. A ferrous alloy steel as claimed in claim 1 having the followingapproximate chemical analysis in weight percentage.

carbon 2.90% silicon 0.97% manganese 0.37% sulfur 0.03% phosphorus0.007% chromium 2.96% molybdenum 2.03% vanadium 8. 60%.

7. An abrasion resistant article formed by forging, austenitizing,quenching and tempering a ferrous alloy steel having a composition asclaimed in claim 1, said article having a substantially martensiticstructure, a Rockwell C hardness within the range of 59 to 67 and agrindability index not exceeding approximately 0.3.

8. An abrasion resistant article formed by forging, austenitizing,quenching and tempering a ferrous alloy steel having a composition asclaimed in claim 2, said article having a substantially martensiticstructure, a Rockwell C hardness within the range of 59 to 67 and agrindability index not exceeding approximately 0.3.

9. An abrasion resistant article formed by forging, austenitizing,quenching and tempering a ferrous alloy steel having a composition asclaimed in claim 3, said article having a substantially martensiticstructure, a Rockwell C hardness within the range of 59 to 67 and agrindability index not exceeding approximately 0.3.

10. An abrasion resistant article formed by forging, austenitizing,quenching and tempering a ferrous alloy steel having a composition asclaimed in claim 4, said article having a substantially martensiticstructure, a Rockwell C hardness within the range of 59 to 67 and agrindability index not exceeding approximately 0.3.

11. An abrasion resistant article formed by forging, austenitizing,quenching and tempering a ferrous alloy steel having a composition asclaimed in claim 5, said steel haaving a composition as claimed in claim6, said article having a substantially martensitic structure, a RockwellC hardness within the range of 59 to 67 and a grindability index notexceeding approximately 0.3. l k 5*

1. A FERROUS ALLOY STEEL HAVING THE FOLLOWING CHEMICAL ANALYSIS:
 2. Aferrous alloy steel as claimed in claim 1 in which the ratio of chromiumto molybdenum is within the range of 1.35 to 1.85.
 3. A ferrous alloysteel as claimed in claim 1 having the following chemical analysis:
 4. Aferrous alloy steel as claimed in claim 3 in which the ratio of chromiumto molybdenum is within the range of 1.35 to 1.45.
 5. A ferrous alloysteel as claimed in claim 1 having the following approximate chemicalanalysis in weight percentage:
 6. A ferrous alloy steel as claimed inclaim 1 having the following approximate chemical analysis in weightpercentage.
 7. AN ABRASION RESISTANT ARTICLE FORMED BY FORGING,AUSTENITIZING, QUENCHING AND TEMPERING A FERROUS ALLOY STEEL HAVING ACOMPOSITION AS CLAIMED IN CLAIM 1, SAID ARTICLE HAVING A SUBSTANTIALLYMARTENSITIC STRUCTURE, A ROCKWELL "C" HARDNESS WITHIN THE RANGE OF 59 TO67 AND A GRINDABILITY INDEX NOT EXCEEDING APPROXIMATELY.3.
 8. Anabrasion resistant article formed by forging, austenitizing, quenchingand tempering a ferrous alloy steel having a composition as claimed inclaim 2, said article having a substantially martensitic structure, aRockwell C hardness within the range of 59 to 67 and a grindabilityindex not exceeding approximately 0.3.
 9. An abrasion resistant articleformed by forging, austenitizing, quenching and tempering a ferrousalloy steel having a composition as claimed in claim 3, said articlehaving a substantially martensitic structure, a Rockwell C hardnesswithin the range of 59 to 67 and a grindability index not exceedingapproximately 0.3.
 10. An abrasion resistant article formed by forging,austenitizing, quenching and tempering a ferrous alloy steel having acomposition as claimed in claim 4, said article having a substantiallymartensitic structure, a Rockwell C hardness within the range of 59 to67 and a grindability index not exceeding approximately 0.3.
 11. Anabrasion resistant article formed by forging, austenitizing, quenchingand tempering a ferrous alloy steel having a composition as claimed inclaim 5, said article having a substantially martensitic structure, aRockwell C hardness within the range of 59 to 67 and a grindabilityindex not exceeding approximately 0.3.
 12. An abrasion resistant articleformed by forging, austenitizing, quenching and tempering a ferrousalloy steel haaving a composition as claimed in claim 6, said articlehaving a substantially martensitic structure, a Rockwell C hardnesswithin the range of 59 to 67 and a grindability index not exceedingapproximately 0.3.